David forbes



DAVID tonnes, or rota PLACE, PORTMAN SQUARE, AND ASTLEY rns'roNf PRICE, or LINco-LusINN-rIELDs,ENGLAND.

I1 ll Letters Patent No. 113,416, dated April 4, 1871'.

IMPROVEMENT IN THE TREATMENT OF SEWAGE AND THE MANUFACTURE 3F FERTILIZERS:

The Schedule referred to in these Letters Patent and making part of the same.

' We, Davin FORBES, consulting engineer, of ,York Place, Portman Square, and As'rnn'r Pas'ros Pinon,

consulting chemist, of 4,7 Lincolns-Inwhields, both in the county of Middlesex and Kingdom of England, have invented Improvements in the Treatment of Sewage and in the production of compounds capable of being employed as manures, or which the following is a specification. a

Oursaid invention rclatcs'- I First, to the preparation and treatment otnatural products, consisting essentially'ot' phosphates of alumina, such, for example, as occur inthe West Indian islands; or of other natural phosphates, such; as the phosphates containing ohosphate or iron orphosphate of lime, or mixtures oi the same; orof phosphate'oi' iron orphosphate of lime and phosphate of alumina,- or mixtures of the same, so as to render the same.

useful for the treatment of sewage and consists in subjecting such natural phosphates oi'alumina' or other natural phosphates, as before mentioiied, to the action of sulphuric acid or of hydrochloric acid, or of mixtures of the same; and in the employment of the resulting products, either alone or in conjunction with a base,

. such as lime; or with carbonate of lime or magnesia,

or carbonate of magnesia or dolomite, for the treatmerit of sewage, in order that certain constituents of the sewage may be thereby removed and be rendered available as fertilizing agents for agricultural purposes.

In carrying out this first part of our invention we first submit to the action of sulphuric acid, h'ydrochloric, acid, or of mixtures of the same, the natural phosphates of alumina or other natural phosphates,

as before mentionechwhiehphosphates are capable of being. decomposed and rendered soluble by the employment of suchacids; Having converted the phosphates into a soluble condition,'or having obtained a solution of the phosphates, they may be either em-. ployed in their concentrated form, or a solution of the same may be diluted, and they-are; then in a fit and proper condition to be employed for the treatment of sewage. i I

While the sewage is contained in a cistern or rese'rvoir, or while it is in the act of flowing thereinto, the requisite proportion of the 'soiublephosphates of alumina is' to bcaddcd thereto; and-after thorough admixture with the sewage by the useot' agitators or other well-known means, the sewage so treated may be allowed to remain tranquil in thereservoir in order that subsidence of theresulting precipitate may be effected; or after having added to the sewage the, requisite amount of soluble phosphates, a base, such,

for example, as lime or carbonate oi'li me- -hut by preference in the form 0f-milk-of-li1ne--1s to be added in such quantity as that the phosphates iii-solution shall be precipitated.

This result will be known by the sewage acquiring 'a neutral or alkaline reaction; or the lime may he firstaddechand the solution of the phosphates added subsequently; but we prefer the former process; or the soluble phosphates may be first decomposed by means of lime or carbonate of lime, or otherwise, and the resulting precipitate may be employedfor the purpose of effecting the separation of certain constituents of Sewage. u

In conjunction with any of the before-mentioned methods ofcarryiug out our-invention, deodorizing agents, such, for example, as animal or vegetable-charcoal, may be employed but good l'BSllliiS'Wlli be obtained by the employment of the phosphates of alullllllil/ alone or in conj unction with lime, as before mentioned.

The sewage after treatment by either of thebeforementioned processes is allowed to settle, and the clear or supernatant water may be run off, and the deposit or precipitate collected and removed and employed, for agric ultnral purposes, either in the moist condition or after having been submitted to a drying dcsiccating 1 process; or the precipitated phosphates may be again submitted to the action of sulphuric acid or hydrochloric acid, or of mixtures of the same, and thesolution be again employed for the treatment ct sewage in a manner similar to that before described.

The proportions in which the soluble phosphates may be employed will vary with the sewage to be operated upon and the quality of the manure desired to be obtained.

\Ve have obtained good results by the employment of about two parts by weight ofthe soluble phosphates submit such before-mentioned natural products to the action of sulphuric or of hydrochloric acid, or of mixtnres of the same, so as to effect the solution of the soluble phosphates of alumina thereon contained, and after separat-hig,if necessary, the insoluble portions from the solution, we then effect the precipitation of the phosphates held in solution, or which have been same manner the phosphates otherwise. I y

We would. state we wish it to he understood that we do not'claim tlle treatnient of phosphatesof alu' mina generally; 113st confine onrselyesto the treatment of phosphates of alumina, such as or similar tothose which are obtained, iirom the sources mentioned.

Having now deseribed and particularly ascertained the'nature of the said invention, and: the manner in which the same is 01 inay be used or carried into effect, we'would observe, in conclusion, that What 'we considerto be novel and original, and

The precipitmhed phlosphates t-h us obtained may be employed as ma Therefore claim as the invention,is- 1. The treatmentof sewage or the production of manures by the use of the natural phosphates of alumina and of other natural phosphates, such as herestantially in the manner herein described-that is to say, by first submitting such natural phosphates to the. action of'zsulphnric acid, hydrochloric acid, or mixtures of the same, and employing such resulting such as lime, forthe purposes set forth.

alumina, such as herein referred to, forthe product-ion ingagents-in the manner hereinhefore described.

In testimony whereof we have signed our names to witnesses. I

DAVID FORBES. ASTLEY PASTON PRICE.

Witnesses:

WM. D. WOOD, F. ROWLAND.

inbef'orc mentioned, or mixtures of the samefsub- -produc ts either alone or 'in .conjunction with a base,

- 2. The treatment of those natural phosphates of" of compounds capable of being employed as fertiliz this speeificationin the presence-of two subscribing. 

